Review usage of packages (files) and directories in Python

[alexjpwalker]

Problem to Solve

Our Python project structure doesn't currently feel very "Pythonic". In Python, it's conventional to have fewer files, because Python packages are files.

Current Workaround

We have a hybrid model - some of our directories (eg: grakn, grakn/common) use a more Python-like structure where a file is used as a package and contains multiple related classes (eg: client.py, exception.py); other directories (e.g. concept) use a more Client Java-like structure where a directory contains multiple related packages which each contain a single class.

The case where this gets really ugly is Concept; we write from grakn.api.concept.concept import Concept.

Proposed Solution

We may well determine that the hybrid model is the right way to go - it was designed as a trade-off between conformance to Java and elegance in Python - but we should check, ideally with people with good Python experience.

[alexjpwalker]

Python file structure is generally quite similar to Rust. We should revisit this once we're done with Rust.